Optimization of Coagulation and Flocculation Process in Wastewater Treatment of the Food Industry: A Laboratory Study

Food industry wastewater has a high pollution load, which is due to water consumption at various stages. In the absence of adequate wastewater management and supervision of the food industry, this wastewater can be considered as a source of environmental pollution. This study aimed to optimize the coagulation and flocculation process for the treatment of food industry wastewater.

The present study was a laboratory study. Aluminum sulfate and poly aluminum chloride were used as coagulant and cationic poly-electrolytes C-270 and anion A-300 were used as coagulant aid. Then, the optimization of pH (4.5-10.5), coagulant concentration (300-800 mg/L) and coagulation aid (3-8 mg/L) were evaluated by calculating optimal removal efficiency of turbidity, total suspended solids and chemical oxygen demand. And the results were analyzed using Pearson’s correlation coefficient.

The results showed that at optimal pH (8.5), poly aluminum chloride concentration (600 mg/L) in combination with cationic poly-electrolyte C-270 (5 mg/L), removal efficiency for turbidity, TSS and COD parameters were 98.75%, 98.5%, and 82.4%, respectively.

It can be concluded that using poly aluminum chloride as a coagulant and cationic polyelectrolyte C-270 as a coagulant aid can be used as an appropriate pretreatment for reducing the organic load for food industry sewage.